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Requirements for Quick Network Construction Mechanisms for the On-Site Emergency Rescue Activity Keiichi Shima, Yojiro Uo Internet Initiative Japan Inc. Background Increasing threats of natural disasters in urbanized cities
Keiichi Shima, Yojiro Uo Internet Initiative Japan Inc.
crawlers
connected by a joint with high degree of freedom
in disaster areas
must have redundant paths in case of AP failure
possible to recover from failure using redundant routes
a new AP has to be added to recovery point
sharing is needed to find the proper location of the new AP
Failure Notification
leave from
attempt if the
attempt if no robot is under control
communication delay at maximum
network
and jitter network
Through Time Delay: Review and Prognosis,” IEEE Transaction of robotics and automation, Vol.9,No. 5, pp.592–606, October 1993.
controlled in real-time
the predictive control method
bandwidth and can live with high delay
can live with high delay
Yaesu Underground Mall (about 300m x 300m)
about 50m (802.11a case, without any
reach 25m, we need 144 nodes to cover entire area
300m 300m 25m
take the link quality into account
there may be existing wireless devices that are not used any more and interferes the Robohoc connection
Negative routing information Negative routing information Control message
Target
AP distribution
RHRs and robots cannot be located uniformly. The Robohoc network must support the non- flat node distribution. (Section 3.1)
Communication distance
The distance between teleoperators and robots is from a few hundreds meters to about 1
Network partitioning
The Robohoc network may be partitioned while constructing the network or operating rescue
Real-time robot control
For real-time robot control, the network latency has to be less than 400ms. Robots can be controlled even the latency is more than 400ms using how- ever, in that case, the latency has to be predictable and stable. (Section 3.4)
Type of service support
The Robohoc network must be able to provide different traffic properties for different contents, for example, the real-time delivery for the robot control and the wider bandwidth for the live streaming. (Section 3.4)
Topology information sharing and storing
When recovering from partitioning, teleoperators, APs and robots have to know the topology of the network to find the failure point. The topology information must be shared and stored in every node. (Section 3.6)
Bootstrap and auto- configuration
The network construction and rescue activities must be started as soon as possible. Every node must start with minimum manual configuration and must have an auto-configuration property. (Section 3.7)
Hop counts
The number of RHRs in a Robohoc network may be more than 100. The average hop count in this case would be more than 20. To support a wider area, the number of hops and average hop count will increase. (Section 3.8)
Layer 2 information utilization
The Robohoc network uses a wireless communication media to create the network. Each RHR has to monitor the link quality of their connections and utilize the information for better performance. (Section 3.9)
Fault Tolerance
The Robohoc network must not have a single point of failure. The network must be able to recover from partitioning either by the human intervention or by autonomous recovery actions of robots. (Section 3.10)